EDEN PRAIRIE, Minn. - After starting 15 games at safety for the Minnesota Vikings last season, Jamarca Sanford was hoping that he would get the chance to prove he had made significant strides during the offseason.

The hard-hitting Sanford spent that time paying extra attention to his cardiovascular conditioning and working on his core muscles in order to gain flexibility.

But Sanford's hard work wasn't enough to earn him a starting job. He lost the training-camp competition for the strong safety job to Mistral Raymond and was told that he should focus on contributing on special teams.

"It tore me down, I'm not going to lie," Sanford said. "It took me a minute to get over. Like the first three days, I was just dead. I was just looking for an answer. Like what I didn't do right or what I did wrong. Because I know I had worked that hard this offseason to come back to start.

"I just had to be strong and knew that I did everything I could do to start. It just didn't work out. Things just don't always work out like you plan them to. I knew I had put in the work, and I knew when my opportunity came I just had to show them that I'm ready to go."

Sanford's opportunity came in the Vikings' 24-13 victory over San Francisco on Sunday at the Metrodome.

Raymond crumpled to the turf in the second quarter after attempting to tackle 49ers running back Frank Gore with what appeared to be a serious injury to his right ankle. Tests showed Raymond had a severe bone bruise and an apparent dislocation. The good news was that there was no break and he won't need surgery.

Still, it will be Sanford starting alongside rookie first-round pick Harrison Smith on Sunday at Detroit and likely in the coming weeks.

Sanford finished Sunday's game with six tackles, forced a fumble by Gore in the fourth quarter that linebacker Marvin Mitchell recovered and also contributed a tackle on special teams.

About the only miscue was that Sanford was covering 49ers standout Vernon Davis when the tight end caught a 20-yard pas that put the ball at the Vikings 1-yard line and set up San Francisco's only touchdown.

"I thought he did a good job when he got in there," Frazier said. "He had the one play down the sideline with Davis, who presents a lot of problems for anybody that tries to cover him in a one-on-one situation. But other than that he tackled well, had a big tackle against Gore in the open field which was good to see. He was good on his assignments."

It was Frazier who ultimately decided that Sanford wasn't worthy of a starting job coming out of training camp. There never has been any question about Sanford's willingness to hit or his ability against the run.

But Sanford has struggled against the pass -- the Vikings safety play certainly was subpar in 2011 -- and the coaches ultimately thought the 6-foot-1 Raymond was a better fit for their defense than the 5-10 Sanford.

Sanford, a seventh-round choice of the Vikings in 2009, is an interesting guy because while he is one of the Vikings' biggest trash-talkers on the field, he comes off as a thoughtful person off of it. Sanford doesn't duck the media and doesn't give clichéd answers.

On Monday, Sanford declined to get into specifics of what he was told by Frazier and defensive coordinator Alan Williams when he was informed that Raymond had beat him out for the starting spot. But Sanford did acknowledge that his best friends on the team, Percy Harvin, Jasper Brinkley and Erin Henderson, were all there for him and lent their support.

"They stayed in my ear," Sanford said. "All of them said, 'Just keep working.' I just kept working and kept preparing every week like I was going to play. I already knew I was one play away (and that if) either safety got hurt I was going to be in there. So I just kept preparing and my opportunity opened up. I'm just trying to take advantage of it."

Whatever Harvin, Brinkley and Henderson said to Sanford it clearly helped. He had every opportunity to feel bad for himself, but instead dedicated himself to being a solid contributor on special teams.

"Jamarca really had his heart set on being a starter this season," Frazier said. "He worked his tail off throughout the offseason. He was really looking forward to it and there's no doubt there was disappointment when he wasn't named one of the starters at safety. I tried to encourage him when we made the decision to let him know how quickly things can change in our league.

"Keep your head up, keep working hard and to his credit, he's done that. He's had a good attitude, he wanted to be on the field, but he understood why we did what we did. Why we went in the direction we did. ... what he did on special teams, what he has done, in absence of being a starter, just a great example for the rest of our team."

Sanford thinks the coaching staff will like what it sees with him starting, too.

He ordinarily spends his offseason lifting weights, but this past summer he decided to change that.

"I came back in better condition I believe," he said. "I normally live in the weight room. This offseason I worked on my cardio a lot and I slimmed up, lost my body fat. Just really focused on my body and being in condition ready to go all day. ... (The coaches) told me to be ready to improve on covering tight ends. I felt like in training camp I did that.

"I showed improvement and felt like I was bending better and just having a better feel for the game. I went back and looked at my DVD. (Defensive backs coach) Joe Woods always sends us (a DVD) in the offseason so we can study ourselves. It just seemed there were a lot of plays where I was tired or playing high and I just came back this year and just focused on (improving) my weaknesses."